postIDiv is deprecated, use postScale

Temp CL until this can land: https://skia-review.googlesource.com/c/skia/+/260998

Change-Id: Ice6365c6827f85f57ccf2f44fe94a7a54ab0231c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1975041Reviewed-by: David Reveman <reveman@chromium.org>
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Mike Reed <reed@google.com>
Cr-Commit-Position: refs/heads/master@{#726464}

components/exo/surface.cc

@@ -968,7 +968,9 @@ void Surface::UpdateBufferTransform(bool y_invert) {
   }
   if (y_invert)
     buffer_matrix.preScale(1, -1, 0.5f, 0.5f);
-  buffer_matrix.postIDiv(state_.buffer_scale, state_.buffer_scale);
+  if (state_.buffer_scale != 0)
+    buffer_matrix.postScale(1.0f / state_.buffer_scale,
+                            1.0f / state_.buffer_scale);
   buffer_transform_ = gfx::Transform(buffer_matrix);
 }